How to Enable the disabled Next button in NSIS? - nsis

Question

In My custom page, I have disabled the next button while the page loading... Because there is some background process need to complete, until we cant go to the next page. So I have disable the next button using following code.
GetDlgItem $1 $HWNDPARENT 1
EnableWindow $1 0
But I want to enable the next button once background process completed. I have used the follwoing code to enable
GetDlgItem $1 $HWNDPARENT 1
EnableWindow $1 1
But it was not worked... cld u please suggest the mistake done by me or how achieve this in NSIS?
Following is My Code
Function StartProgressPage
; Set dialog text:
!insertmacro MUI_HEADER_TEXT "$(STARTPRGDIA_TITLE)" "$(STARTPRGDIA_SUBTITLE)"
; Display the page:
!insertmacro MUI_INSTALLOPTIONS_DISPLAY "StartPrgDia"
;Disable Next Button
GetDlgItem $0 $HWNDPARENT 1
EnableWindow $0 0
nsDialogs::Create 1018
Pop $dialog
nsDialogs::CreateControl "msctls_progress32" \
${DEFAULT_STYLES}|${PBS_SMOOTH} \
${PB_EXSTYLE} \
0 30 100% 10% \
"Test" \
Pop $hwnd
${NSD_CreateTimer} NSD_Timer.CallStop 10
nsDialogs::Show
FunctionEnd
Function NSD_Timer.CallStop
${NSD_KillTimer} NSD_Timer.CallStop ; Kill the timer
SendMessage $hwnd ${PBM_SETRANGE32} 0 100
SendMessage $hwnd ${PBM_SETPOS} 25 0
Call <Some Process>
SendMessage $hwnd ${PBM_SETPOS} 50 0
Call ConfPropertyChanges
SendMessage $hwnd ${PBM_SETPOS} 100 0
${NSD_CreateLabel} 0 10 20% 10u Completed
;Enable Next Button
GetDlgItem $0 $HWNDPARENT 1
EnableWindow $0 1
FunctionEnd

Answer 1

As far as I know installer will wait inside this code:
!insertmacro MUI_INSTALLOPTIONS_DISPLAY "StartPrgDia"
until user goes to the next page.
Are you sure that the code bellow this line is executed when custom page is displayed?
You should call
!insertmacro MUI_INSTALLOPTIONS_DISPLAY "StartPrgDia"
after all your code or use this(MUI2 version)
Function CustomPage
!insertmacro INSTALLOPTIONS_INITDIALOG "page.ini"
# your code here
!insertmacro INSTALLOPTIONS_SHOW
FunctionEnd